The invention relates to article handling and, more particularly, to a truss stacker (or alternatively referred to also as, a truss stacking system).
It is an object of the invention to provide a single side truss stacker.
It is another object of the invention to provide a process line of plural single side truss stacking stations working to the side of (or straddling) a conveyor carrying an outflow of freshly made trusses from a truss making plant.
Single side truss stacking makes sense to conserve workspace in the work yard where the trusses are stacked. In a typical work yard, the land vehicles require much more real estate than the line of truss stacking stations. The land vehicles include the fork trucks that lift the stacks of trusses and the semi-tractors and flat bed trailers on which the fork trucks load the stack of truck from delivery away from the plant. Stacks of large trusses nowadays often require two, sometimes three, fork trucks working in concert. The amount of space required to make a 90° pivot, let alone a 180° pivot, is substantial.
So as a practical matter, it is impractical to stack on both sides of the process line because the real estate needs of the land vehicles is so great that the overall size of the work yard would be twice what a single side truss stacking line requires. In other words, the size of the work yard can literally be halved for a single side truss stacking line. The single side truss stacking line can be set up along a property line or the like where the work yard is landlocked, thereby maximizing the rest of the real estate that is available for the maneuvering of the large heavy land vehicles.
It is a further object of the invention to avoid hydraulics as well as scissor jacks. It is a corollary object of the invention that the power needs are met by electric power supply to electrodynamic appliances that power such drive trains utilizing any of gear, sprocket, spindle, chain, cable and so on:—but not hydraulics or scissor jacks.
It is a further object of the invention to configure the outflow conveyor as a series of generously spaced hurdles wherein the cross bar of which are rollers. Spacing which is generous is in the neighborhood of six feet (˜2 m) and greater. However, less generous spacing will serve the purpose. In the preferred embodiment, every other roller is driven, and the alternate rollers are idlers. In any event, not every roller need be driven. This spacing between the rollers provides the advantage of allowing workers to comfortably walk between spaced rollers. Among other reasons for facilitating pedestrian traffic between rollers includes the following. If for any reason any of the truss lift sub-stations stops working or else is taken offline (as for maintenance or the like), workers can still work manually in teams to lift off trusses transiting on the outflow conveyor and carry the trusses sideways to the stack forming sub-station. And the conveyor will pose no impediment to the manual lift and carry operation.
Preferably the driven rollers all have their own independent drives. They should turn at more or less the same speed, but exact precision is not needed.
A number of additional features and objects will be apparent in connection with the following discussion of the preferred embodiments and examples with reference to the drawings.